The present invention relates to a power take-off, in particular for industrial vehicles.
Power take-offs in industrial vehicles are usually applied directly to the gear change. They receive in input a torque of a certain rotation speed provided by the vehicle gearsn and transmit it in output, by means of special organs therefor, to one or more users. In particular the power take-offs exhibit a first output organ, to which an air compressor can be connected, and a second output organ, to which a pump or other hydraulic user can be connected. Both users can be connected directly to the power take-off.
Normally the velocity ratio between the power take-off and the drive shaft of the gears for use of the compressor is comprised between 1.4 and 1.8:1, while the ratio for the use of the hydraulic pump is comprised between 0.8 and 1.6:1. Both the users, compressor and pump, can be connected and disconnected to and from the output organ of the power take-off by means of special connector devices. Activation of the connector devices is normally pneumatic.
At present there do not exist large-size air compressors, i.e. able to process air flows in the order of 200-800 m3/hour, directly connectable to the power take-off fixed on the gear change of industrial vehicles. This is due to the high weight of the compressors, provided with a circuit and a lubrication pump, a torque limiter and a stage of reduction in input, which normally reaches 150 kg.
Large-size compressors are therefore connected to the frame of the vehicle by support brackets. Transmission of torque and rotating motion of the output organ of the power take-off to the compressor is achieved via a drive shaft. This leads to a certain complication in the compressor connection to the power take-off, as well as a further increase in the overall weight and mass of the power take-off and the compressor.
The aim of the present invention is to provide a light and compact power take-off which enables projecting connection of a user, in particular a compressor able to process flow-rates of the order of 200-800 m3/hour, without any need for brackets or other support means.